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Old 07-21-2009 | 10:55 PM
  #1016  
stevo revo
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Joined: May 2008
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From: West Bend, WI
Default RE: Phoenix Extra 330S 60-90 Size

min$2crash.........this is my second one.... but the first one died last year in June.... not even 3 weeks old. Switch failure, I believe. Thanks for the compliments!! This one I have been flying since July of last year. I agree about the ax mufflers too. A guy in the club modified his stock muffler and TOTALLY killed the power of that motor. Made it like a .90 or less.

So I did get the maiden in tonite between rain showers. Mainly wanted to get some more rich tanks through it. Motor ran well, even being rich. I kept her on low rates so I would behave and concentrate on just flying the pattern to get the fuel through it. Ill start to wring her out after I get at least 5 good rich tanks through her.

I also went through the linkages and made sure all was well in that department.... thanks cmoulder for the reminder.

All went well..... except the cg is just a mess.

Cmoulder this is aimed at you, I'd like your opinion on this one.........

I set my cg at 120mm EXACTLY, which is almost 4.75 inches..... without fuel of course. I run a 16 oz tank in the nose, and the header tank is now gone. So I fueled her up, and got her off the ground. Did a few quick trim adjustments and had her straight and level at 1/3 throttle. Air was completely dead, so easy to trim and check out a few things. First I played with power on and off, to check up and down thrust angles (which is currently zero). The aircraft maintained a straight and level path when at wot or at a low throttle setting (not idle). Good there. Then I rolled to inverted to check cg, and I only had to maintain a slight bit of down elevator to hold it.

As I continued to fly out the tank, she started to drag her tail, more and more, like a dog does when.....well you know. Anyway it just continued to get progressively worse. It got so bad that at a low power setting it would just pitch the nose up until it stalled.

I brought it in for landing, and lets just say it was a bit tricky even without wind. I had to keep power on and push the nose down to keep her level. Total crap.

I refueled and took her up again to try landing with a full tank, and it was just fine...... hmmmm I said......

I made the horrible mistake when I tore out the old engine..... I didnt check ANYTHING.... cg, thrust angles, nothing. I was in too much of a hurry to get started. So I have no idea where my cg was set at before.

Anyway, when it was flying around dragging its tail, I was thinking about your incidence change on the wing........

This case seems more like a bad cg placement to me. I brought the plane home and I checked cg with a full tank of fuel. It came in at about 4 1/8 inches..... about 5/8 more foreward than the book calls for.

I really think the way to go with this is to set the cg at 4 1/8, DRY, and I might even try to bring the tank back against the wing tube, to minimize the effect on cg later in flight. I will run 1/8 line to be sure not to restrict fuel supply.

Im still debating on the incedence change though. The plane used to fly much better later in the tank of fuel..... but I never usually got below half and now I can suck it dry with a rich 1.20. It still used to drop its tail though on landing, but nowhere this bad.

So what do you think? Wouldnt the incidence change worsen this? You are raising the te of the wing, which is already high in relationship to the fuse when landing.......you've done it though, so it must work. I just dont quite understand the mechanics of it...........could you explain it a bit?

Btw, sorry about the novel.... I hate super long posts as much as the next guy..............